Hello All AIPMT Biology Aspirants, next topic to learn is Pancreas.
- It lies posterior to the greater curvature of the stomach, between the limbs of the ‘U’ shaped duodenum.
- Pancreas is an elongated and somewhat flattened organ that consists of a head, body, and tail.
- It functions as both an endocrine gland (secreting hormones into the extracellular fluid) and an exocrine gland (secreting digestive juices through the pancreatic duct to the gut lumen).
- As an endocrine gland, it secretes insulin and glucagon; hormones that help keep the blood glucose level within normal limits.
- The exocrine tissues of the pancreas secrete pancreatic juices, a host of digestive enzymes, including lipases, amylases, proteases, and nuclease.
- Exocrine cells secrete pancreatic juice into small ducts that ultimately unite to form two ducts.
- The Pancreatic duct, or Duct of Wirsung, is the larger of the two ducts.
- Pancreatic duct joins the common bile duct from the liver and gallbladder and enters the duodenum as a dilated common duct called the Hepato-pancreatic duct/Hepato-pancreatic ampulla or Ampulla of Vater.
- The passage of pancreatic juice and bile through the hepato-pancreatic duct into the duodenum of the small intestine is regulated by a mass of smooth muscle known as the Sphincter of Oddi.
- The other duct of the pancreas, the Accessory duct (Duct of Santorini), leads from the pancreas and empties into the duodenum superior to the hepatopancreatic duct.
- Pancreas is made up of small clusters of glandular epithelial cells. About 99% of the clusters, called Acini , constitute the exocrine portion of the organ. The cells within acini secrete a mixture of fluid and digestive enzymes called pancreatic juice. The remaining 1% of the clusters, called Pancreatic islets (Islets of Langerhans) form the endocrine portion of the pancreas. These cells secrete the hormones glucagon, insulin, somatostatin, and pancreatic polypeptide.